Synchronization monitoring in a network element
US5917870A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 17, 1995 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Nov 17, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J2203/0089
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In digital transmission systems, such as synchronous transmission systems according to the SDH/SONET standard, there is a need to have information on the synchronization status of the system. A known approach is to monitor the pointer activity. This is disadvantageous in that because of a hysteresis in the pointer processor, information derived from the pointer activity only conditionally reflects the synchronization status. In a network element (1) according to the invention which forms part of a transmission system of the above type, at least one interface unit (2, 3, 4) contains, besides an optical-to-electrical transducer (5), a synchronization-monitoring device (6) which derives a synchronization status parameter, e.g., TIE, RMSTIE, by comparing an external clock frequency (T.sub.e) with an internal clock frequency (T.sub.i). For this, the synchronization-monitoring device (6) comprises a phase-comparing device (37), a memory device (25), and an evaluating device (26).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.